As disclosed in U.S. Pat. Nos. 4,439,617 (Sestanj et al.), 4,592,866 (Cale), and 4,663,452 (Lilje), German Patent No. 741,109 (Dieterle), and Scheeren et al., Synthesis, 1973, pp. 149-151, it is known that carbonyl compounds can be converted to the corresponding thiono compounds by reaction with tetraphosphorus decasulfide (more commonly, though less accurately, known as phosphorus pentasulfide).
Scheeren et al. teach that the reaction rates can be increased by conducting such thiations in the presence of sodium sulfide, carbonate, or bicarbonate and a polar solvent, Dieterle discloses the use of alkaline earth carbonates and oxides in such thiations to increase yields, and Lilje teaches that both the reaction rates and yields can be improved by conducting such thiations in the presence of an alkali metal bicarbonate and a hydrocarbon diluent.
Copending application Ser. No. (Case 5865) (Stahly) and Ser. No. (Case 5956) (Stahly), filed , 1989, disclose the use of diatomaceous earth, zeolites, molecular sieves, and Group IIA metal fluorides as thiation adjuvants in carbonyl compound/phosphorus pentasulfide reactions which may be conducted in the presence or absence of a polar or non-polar diluent.
In the aforementioned thiations, as well as in other known thiations of carbonyl compounds, it has been found that the recovered yield of thiono compound is apt to vary widely for no apparent cause and that the amount of thiono compound actually obtained from the thiation reaction is therefore frequently much less than the amount present in the reaction mixture at the end of the reaction.